Preangerian (late Miocene) Mollusca from a hill near Sekurau, northern Kutai, Kalimantan Timur (East Borneo)

Molluscan fossils deriving from the western foot of a hill near Sekurau, northern Kutai, were collected by Dr M. Schmidt in 1902 in a Late Miocene succession of clayey/sandy deposits with some limestones and sandstones, overlain by Pliocene coral limestones whose fossil content has been described before. Sixty Miocene species are discussed, their combined stratigraphic ranges strongly suggesting a Preangerian age (Tf3), the fauna perhaps being a little younger than the fauna of the Gelingseh Beds from Sungai Gelingseh (to be described in a forthcoming paper) and nearer in age to Muara Kobun, recently described. The fauna would appear to have lived under sub-littoral conditions. A few new species and a new subspecies are described: Eunaticina visenda, Ancilla schmidti, Marginella vultuosa, Clathrodrillia kutaiana, Cythara zothecula, Dentalium javanum tutongense, and Portlandia carolimartini.